added toString to assist debuggin

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@24795 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/model/Queue.java

@@ -1233,6 +1233,11 @@ public class Queue extends ResourceController implements Saveable {
             this.future = new FutureImpl(task);
             return this;
         }
+
+        @Override
+        public String toString() {
+            return getClass().getName()+':'+task.toString();
+        }
     }
     
     /**